Comparability of mortality statistics over time is affected by a number of factors. These include issues relating to the collection, classification and processing of the data. In the late 1990's, there were two major changes within Australia, namely, the introduction of the tenth revision of the International Classification of Diseases (ICD-10) for classifying deaths registered from 1 January 1999 and the introduction of the Automated Coding System (ACS) for processing deaths registered from 1 January 1997.

Introduction of Automated Coding and ICD-10

Columns from sheet

Coding Method

ICD revision

Comments

1979-1996

Manual

ICD-9

Prior to 1979, manual coding under relevant ICD revisions.

1997-1998

Automated

ICD-9

Comparability factors between manual and automated ICD-9 coding were produced, based on a sample of dual coded 1997 data.

As a consequence of the coding of deaths registered in 1997 and 1998 to ICD-10 as well as ICD-9, there is now a single break in time series outlined in the table below.

Time Series

Columns from sheet

Coding method

ICD revision

1979-1996

Manual

ICD-9

1997-onwards

Automated

ICD-10

To support this single break in series, the following table provides concordances and comparability factors for all groupings in this publication. The concordance illustrates the conceptual differences between ICD-9 and ICD-10 classifications. The comparability factors are derived from the movements in the underlying causes of death coded in ICD-9 compared to ICD-10. Groupings with very small numbers have been annotated with an asterisk (*). Caution should be exercised when comparing the two versions of ICD for these groupings.

Additional concordance tables at the three and four digit level between records coded to ICD-9 and ICD-10 are available on request. Further information or clarification on the concordance between these revisions is available from the ABS on 1800 620 963.

COMPARISON OF NINTH AND TENTH REVISIONS OF ICD

The introduction of ICD-10 has resulted in changes to the interpretation and resultant coding of a number of causes, as outlined in the WHO publication International Statistical Classification of Diseases and Related Health Problems Tenth Revision, Volume 2. Causes most affected are Asthma, Mental and behavioural disorders and Diseases of the nervous system.

Under ICD-10, Asthma more clearly links with Chronic lower respiratory diseases, especially Bronchitis and Emphysema. Where these conditions are present, Chronic lower respiratory diseases takes precedence, resulting in a decrease in the reporting of asthma as the underlying cause.

The Chapters covering Mental and behavioural disorders and Diseases of the nervous system have undergone compensatory changes between ICD-9 and ICD-10, mainly due to Alzheimer's disease and certain dementias moving between these Chapters.

Concordance and comparability factors

ICD-10 Code

ICD-9 Code

Comparability factor

All causes

A00-Y98

001-999

1

Chapter I Certain infectious and parasitic diseases

A00-B99

001-139

1

Septicaemia

A40, A41

38

1

Human immunodeficiency virus (HIV) disease

B20-B24

042-044

1

Chapter II Neoplasms

C00-D48

140-239

1

Malignant neoplasms

C00-C97

140-208

1

Digestive organs

C15-C26

150-157,159

1

Oesophagus

C15

150

1

Stomach

C16

151

1

Colon

C18

153

1

Rectosigmoid junction, rectum, anus and anal canal

C19-C21

154

1

Liver and intrahepatic bile ducts

C22

155

1

Pancreas

C25

157

1

Respiratory and intrathoracic organs

C30-C39

160-165

1

Trachea, bronchus and lung

C33, C34

162

1

Melanoma of skin

C43

172

1

Breast

C50

174 175

1

Female genital organs

C51-C58

179-184

1

Ovary

C56

1 830

1

Male genital organs

C60-C63

185-187

1

Prostate

C61

185

1

Urinary tract

C64-C68

188 189

1

Kidney, except renal pelvis

C64

1 890

1

Bladder

C67

188

1

Eye, brain and other parts of central nervous system

C69-C72

190-192

1

Brain

C71

191

1

Lymphoid, haematopoietic and related tissue

C81-C96

200-208

1

Leukaemia

C91-C95

204-208

1

In situ and benign neoplasms and neoplasms of uncertain or unknown behaviour

D00-D48

210-239

1

Chapter III Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism

D50-D89

279,280-289

1

Chapter IV Endocrine, nutritional and metabolic diseases

E00-E90

240-278

1

Diabetes mellitus

E10-E14

250

1

Chapter V Mental and behavioural disorders

F00-F99

290-319

1

Psychoactive substance use

F10-F19

291 292

1

Organic, including symptomatic, mental disorders

303 304 305

Chapter VI Diseases of the nervous system

F00-F09

290

1

Extrapyramidal and movement disorders

G00-G99

320-359

1

Alzheimer's disease

G20-G26

332-333

1

Chapter VII Diseases of the eye and adnexa

G30

3 310

1

Chapter VIII Diseases of the ear and mastoid process

H00-H59

360-379

*

Chapter IX Disease of the circulatory system

H60-H95

380-389

*

All heart disease

I00-I99

390-459

1

Acute rheumatic fever and chronic rheumatic heart diseases

I05-I09,I11,

393-398,402,

1

Hypertensive diseases

I13,I20-I25,

404,410-414,

Ischaemic heart diseases

I26,I27,

415 416

Acute myocardial infarction

I30-I52

420-429

Pulmonary heart disease and diseases of pulmonary circulation and other forms of heart disease

I00-I09

390-398

1

Cerebrovascular diseases

I10-I15

401-405

1

Diseases of arteries, arterioles and capillaries

I20-I25

410-414

1

Atherosclerosis

I21

410

1

Aortic aneurysm

I26-I52

415-429

1

Chapter X Diseases of the respiratory system

I60-I69

430-438

1

Influenza and pneumonia

I70-I79

440-448

1

Chronic lower respiratory diseases

I70

440

1

Emphysema

I71

441

1

Asthma and status asthmaticus

J00-J99

460-519

1

Chapter XI Diseases of the digestive system

J10-J18

480-487

1

Diseases of oesophagus, stomach and duodenum

J40-J47

490-496

1

Gastric and duodenal ulcer

J43

492

1

Diseases of liver

J45, J46

493

1

Chapter XII Diseases of the skin and subcutaneous tissue

K00-K93

520-579

1

Chapter XIII Diseases of the musculoskeletal system and connective tissue

K20-K31

530-537

1

Arthropathies and systemic connective tissue disorders

K25-K27

531-533

1

Chapter XIV Diseases of the genitourinary system

K70-K77

570-573

1

Renal failure

L00-L99

680-709

1

Chapter XV Pregnancy, childbirth and the puerperium

M00-M99

710-739

1

Chapter XVI Certain conditions originating in the perinatal period

M00-M36

710-719

1

Disorders related to short gestation and low birthweight, not elsewhere classified